To evaluate a subterranean formation, a downhole tool may be lowered into a wellbore or borehole penetrating the subterranean formation to measure one or more characteristics or parameters of the subterranean formation such as, for example, formation porosity, formation shear slowness, etc. To acquire data, an acoustic source disposed on the downhole tool generates a signal, which travels through the subterranean formation and returns to the downhole tool.